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  • 1995-1999  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of radioanalytical and nuclear chemistry 220 (1997), S. 47-54 
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Extraction chromatographic supports (XAD-7) impregnated with binary mixtures of cobalt dicarbollide and one of the two phosphororganic extractants (dibutyl-N,N-diethylcarbamoylmethyl phosphonate, DBDECMP, or octyl(phenyl)-N,N-diisobutylcarbamoylmethyl phosphine oxide, (CMPO) were prepared using methanolic solutions of the extractants and subsequent evaporation of methanol at room temperature. The molar ratios (x) in isomolar series of the two extractants were 0, 0.25, 0.5, 0.75, and 1. The sorbents were used for investigating Eu capture from 0.1 and 1M HNO3 solutions under static conditions (24 hours shaking, 2 cm3 aqueous phase with 0.2 g sorbent, Eu initial concentrations 3·10−9, 0.0001, 0.001, 0.01 and 0.1M). The sorbents containing mixtures of extractants corresponding to the interpolated value x=0.45 (phosphororg./dicarb.) exhibited the highest values of the distribution ratios of Eu. A synergic effect of three orders of magnitude for low concentrations of Eu was observed. A tentative determination is given of the nature and the equilibrium constants of the chemical reactions assumed.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of radioanalytical and nuclear chemistry 220 (1997), S. 245-247 
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The kinetics (1–1000 minutes shaking) of 5·10−4M Eu sorption from 0.1M HNO3 onto the support XAD-7 impregnated with approximately equimolecular mixture of DBDECMP and dicarbollide depends appreciably on the technique of the preparation of the impregnated support. The highest distribution factors are obtained if DBDECMP is only used to impregnate the support and dicarbollide is added directly to the aqueous phase. The rate of sorption increases slightly with adding 1·10−5M surfactants but the effect is too weak for practical use. The best stripping agent found is an equimolecular mixture of DCTA and citric acid at pH 7. This work is a continuation of the investigation1–3 of the synergic effect occurring in the sorption of low concentrations of europium due to the simultaneous presence of H+[(C2B9H8Cl3)2Co]− (abbreviated as dicarbollic acid, HB) and di-butyl-N-di-ethyl-carbamoylmethyl phosphonate (DBDECMP) on a suitable support. The system is promising for the separation of small amounts of tervalent transuranium and lanthanoid elements from radioactive waste. In the previous paper we have investigated quasi-equilibrium sorption of various Eu concentrations (24 hour shaking). In the present paper kinetic data of sorption and quasi-equilibrium data on desorption are studied. Preliminary kinetic studies of similar systems2,3 have shown that the rate of both the sorption and desorption processes in this type of system is one of the decisive factors in the practical application of this separation method. Whereas in the previous paper1 both DBDECMP and CMPO (octyl-phenyl-N,N-diisobutyl carbamoylmethyl phosphineoxide) combined with dicarbollide were studied, for reasons given previously1 (mainly a higher synergic effect) herein DBDECMP was only investigated.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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